scholarly journals Comparação do ciclo alongamento-encurtamento em saltos verticais entre mulheres ativas adultas-jovens e idosas

2018 ◽  
Vol 6 (1) ◽  
pp. 15
Author(s):  
Hyago Bernardes da Rosa ◽  
Igor Martins Barbosa ◽  
Eduardo Porto Scisleski ◽  
Samuel Klippel Prusch ◽  
Luiz Fernando Cuozzo Lemos
Keyword(s):  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Vastus Lateralis Muscle ◽  
Electromyographic Activity ◽  
Counter Movement Jump ◽  
Vertical Jumping ◽  
Significant Difference ◽  
Stretch Shortening Cycle

PURPOSE: To verify if there is an electromyographic economy and/or an increase in the variables of vertical jumps, both as a function of the use of the Stretch-Shortening Cycle and to compare the findings between young and old women, both active. METHODS: The sample consisted of a group of elderly (GI) and a group of young (GJ), both female. The power was measured through the contact platform and electromyographic activity of the muscles: biceps femoris (BF), rectus femoris (RF), medial gastrocnemius and vastus lateralis, through vertical jumping tests: Squat Jump (SJ) and Counter Movement Jump (CMJ). RESULTS: All the muscles evaluated did not present a statistically significant difference in the electromyographic activation and the comparisons of the mean percentage of use of the Stretch-Shortening Cycle (CAE), but it was observed that for the vastus lateralis and rectus femoris muscles there were significant differences in the comparisons between the two types of jumps of both groups, GI (236.89±115.66 for SJ and 230.45±109.10 for vastus lateralis muscle (VL) CMJ and 155.42±49.06 for SJ and 155 , 45±61.78 for the CMJ of the RF muscle) required greater neuromuscular activation to jump less than GJ (117.40±133.09 for SJ and 133.09±60.71 for VL muscle CMJ and 106.72±34.15 for the SJ and 108.87±38.85 for the CMJ of the RF muscle). CONCLUSIONS: The present study confirms that there was no statistically significant difference in the use of CAE in both groups (GI and GJ). However, when it comes to the skipped height and the power developed, there were statistically significant differences in the comparison of the groups.

scholarly journals O uso do ciclo alongamento-encurtamento em saltos de atletas de handebol e praticantes de musculação do sexo feminino

2016 ◽  
Vol 85 (3) ◽  
Author(s):  
Hyago Bernardes da Rosa ◽  
Vinícius da Silva Lessa de Oliveira ◽  
Lucas Souza Santos ◽  
Samuel Klippel Prusch ◽  
Igor Martins Barbosa ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Functional Improvement ◽  
Electromyographic Activity ◽  
Squat Jump ◽  
Stretch Shortening Cycle ◽  
Practice Time ◽  
Vertical Jumps

Introdução: O handebol é caracterizado como um esporte de cunho coletivo, possuindo grande variedade de movimentações e seus ganhos propiciam melhoramentos nas qualidades físicas e funcionais. Por outro lado, a musculação, que é amplamente praticada atualmente, possibilita muitos ganhos, porém, proporciona baixo melhoramento funcional. O Ciclo Alongamento-Encurtamento (CAE) está baseado no fato de o músculo realizar ativamente uma ação, sendo parte dessa energia armazenada nos componentes elásticos e reutilizada na próxima ação muscular.Objetivo: Comparar a utilização do CAE na potência dos membros inferiores entre os grupos analisados.Métodos: A amostra foi constituída por 16 atletas de handebol (GH) e 12 praticantes de musculação (GM), ambos do sexo feminino. Foi mensurada a potência através da plataforma de contato e atividade eletromiográfica dos músculos: bíceps femoral, reto femoral, gastrocnêmio medial e vasto lateral, através de testes de saltos verticais: Squat Jump e Counter Movement Jump.Resultados: As diferenças estatísticas significativas encontradas entre os grupos foram: o tempo de prática para o GH foi maior, o tempo de prática semanal para o GM foi superior e o percentual de utilização do CAE que para o GH foi de -2,63 e no GM foi de 13,32, para o músculo vasto lateral.Conclusão: Por meio dos resultados obtidos por testes de saltos verticais, o GH utilizou com maior eficiência a força elástica, apresentando superioridade na economia de ativação do vasto lateral. Portanto, as praticantes de musculação são menos econômicas, possivelmente por seu treinamento isolado.Use Stretch-Shortening Cycle in Leaps Handball Athletes and Female BodybuildersIntroduction: Handball is a sport of collective nature, featuring a great variety of moves and its gains provide improvements in physical and functional qualities. However, bodybuilding, which is commonly practiced nowadays, allows many gains, nonetheless, provides low functional improvement. The Stretch-Shortening Cycle (SSC) is based on the fact that the muscle acts actively, with a part of this energy stored in the elastic components and reutilized on the next muscular action.Methods: The sample was built by 16 handball athletes (GH) and 12 bodybuilding practitioners (GM), both of the womankinds. The potency was measured through the muscular contact and electromyographic activity platform: Biceps femoris, rectus femoris, medial gastrocnemius and vastus lateralis, with vertical jumps: Squat Jump e Counter Movement Jump.Objective: To compare the use of the SSC on the potency of the inferior limbs amongst the analyzed groups.Results: The significant statistical differences found between the group were: the practice time for the GH was higher, the weekly practice time for the GM was higher and the usage percentage of the SSC for the GH was of -2.63 and in the GM was of 13.32, for the vastus lateralis muscle.Conclusion: With the results obtained with tests of vertical jumps, the GH used the elastic force more efficiently, displaying superiority on the activation economy of the vastus lateralis. Therefore, the bodybuilding practitioners are less economic, possibly due to their isolated training.

scholarly journals Evaluation of the Lower Limb Muscles’ Electromyographic Activity during the Leg Press Exercise and Its Variants: A Systematic Review

2020 ◽  
Vol 17 (13) ◽  
pp. 4626
Author(s):  
Isabel Martín-Fuentes ◽  
José M. Oliva-Lozano ◽  
José M. Muyor
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Muscular Activity ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Quadriceps Muscle ◽  
Electromyographic Activity ◽  
Full Extension ◽  
Cross Sectional ◽  
Leg Press

The aim of this study was to analyze the literature on muscle activation measured by surface electromyography (sEMG) of the muscles recruited when performing the leg press exercise and its variants. The Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to report this review. The search was carried out using the PubMed, Scopus, and Web of Science electronic databases. The articles selected met the following inclusion criteria: (a) a cross-sectional or longitudinal study design; (b) neuromuscular activation assessed during the leg press exercise, or its variants; (c) muscle activation data collected using sEMG; and (d) study samples comprising healthy and trained participants. The main findings indicate that the leg press exercise elicited the greatest sEMG activity from the quadriceps muscle complex, which was shown to be greater as the knee flexion angle increased. In conclusion, (1) the vastus lateralis and vastus medialis elicited the greatest muscle activation during the leg press exercise, followed closely by the rectus femoris; (2) the biceps femoris and the gastrocnemius medialis showed greater muscular activity as the knee reached full extension, whereas the vastus lateralis and medialis, the rectus femoris, and the tibialis anterior showed a decreasing muscular activity pattern as the knee reached full extension; (3) evidence on the influence of kinematics modifications over sEMG during leg press variants is still not compelling as very few studies match their findings.

Effect of Cognitive Loading on Single-Leg Jump Landing Biomechanics of Elite Male Volleyball Players

2020 ◽  
pp. 1-6
Author(s):  
Sima Mohammad Amoli ◽  
Peyman Aghaie Ataabadi ◽  
Amir Letafatkar ◽  
Gary B. Wilkerson ◽  
Misagh B. Mansouri
Keyword(s):  
Vastus Lateralis ◽  
Cruciate Ligament ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Acl Injury ◽  
Medial Gastrocnemius ◽  
Cognitive Loading ◽  
Jump Landing ◽  
Landing Biomechanics ◽  
Muscle Activations

Anterior cruciate ligament (ACL) injury is prevalent during the single-leg jump landing in various sports. The effects of cognitive loading and how it affects risk of ACL injury are not well understood. The purpose of this study is to examine how landing kinetics change in the presence of cognitive loading during a volleyball block. Cognitive loading decreased activations in vastus lateralis and rectus femoris, and increased activation in biceps femoris and medial gastrocnemius muscles. During landing, the first and second peaks of ground reaction forces were 13% and 11% lower under cognitive loading, suggesting that cognitive loading alters landing biomechanics and muscle activations.

scholarly journals The Measurement of Stiffness for Major Muscles with Shear Wave Elastography and Myoton: A Quantitative Analysis Study

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 524
Author(s):  
Youngjin Lee ◽  
Minkyoung Kim ◽  
Haneul Lee
Keyword(s):  
Shear Wave ◽  
Shear Wave Elastography ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Voluntary Contraction ◽  
Muscle Stiffness ◽  
Medial Gastrocnemius ◽  
Strong Correlations ◽  
Significant Difference ◽  
The Relationship

The present study was performed to assess the relationship between hand-held myotonometer MyotonPRO and shear wave elastography (SWE) measurements of lower limb muscle stiffness during resting and active voluntary contraction. Forty healthy young adults, (20 males and 20 females) participated in the study. The stiffness of each subject’s rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG) was measured repeatedly by MyotonPRO and SWE. Moderate to strong correlations between the two methods’ measurements were found for both resting and active voluntary contraction. (r = 0.416–0.669, p < 0.05; r = 0.398–0.594, p < 0.05, respectively). Muscle stiffness at rest was significantly lower compared contraction in all four muscles measured by both methods (p < 0.05). Intra-rater reliabilities were generally lower when measurements were taken during contraction. Additionally, when compared by gender, muscle stiffness measured by MyotonPRO was significantly higher at rest in men compared to women, except for the TA. However, a significant difference was found in TA muscle stiffness by gender when measured with SWE. When muscles were contracted, all muscles showed significantly higher stiffness in men compared to women. There were moderate to good correlations in muscle stiffness between measurements of SWE and MyotonPRO at rest and during active voluntary contraction. Additionally, both instruments showed good intra-rater reliability.

scholarly journals Evaluation of lower limb electromyographic activity when using unstable shoes for the first time: A pilot quasi control trial

2012 ◽  
Vol 37 (4) ◽  
pp. 275-281 ◽  
Author(s):  
Helen Branthwaite ◽  
Nachiappan Chockalingam ◽  
Anand Pandyan ◽  
Gaurav Khatri
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Heel Strike ◽  
Electromyographic Activity ◽  
Temporal Parameters ◽  
Unstable Shoes ◽  
First Time

Background: Unstable shoes, which have recently become popular, claim to provide additional physiological and biomechanical advantages to people who wear them. Alterations in postural stability have been shown when using the shoe after training. However, the immediate effect on muscle activity when walking in unstable shoes for the first time has not been investigated. Objective: To evaluate muscle activity and temporal parameters of gait when wearing Masai Barefoot Technology shoes® for the first time compared to the subject’s own regular trainer shoes. Study Design: A pilot repeated-measures quasi control trial. Method: Electromyographic measurements of lower leg muscles (soleus, medial gastrocnemius, lateral gastrocnemius, tibialis anterior, peroneus longus, rectus femoris, biceps femoris and gluteus medius) were measured in 15 healthy participants using Masai Barefoot Technology shoes and trainer shoes over a 10-m walkway. Muscle activity of the third and sixth steps was used to study the difference in behaviour of the muscles under the two shoe conditions. Temporal parameters were captured with footswitches to highlight heel strike, heel lift and toe off. Paired samples t-test was completed to compare mean muscle activity for Masai Barefoot Technology and trainer shoes. Results: Indicated that the use of Masai Barefoot Technology shoes increased the intensity of the magnitude of muscle activity. While this increase in the activity was not significant across the subjects, there were inter-individual differences in muscle activity. This variance between the participants demonstrates that some subjects do alter muscle behaviour while wearing such shoes. Conclusion: A more rigorous and specific assessment is required when advising patients to purchase the Masai Barefoot Technology shoe. Not all subjects respond positively to using unstable shoes, and the point in time when muscle behaviour can change is variable. Clinical relevance Use of Masai Barefoot Technology shoe in patient management should be monitored closely as the individual muscle changes and the point in time when changes occur vary between subjects, and evaluation of how a subject responds is not yet clear.

Arm movements can increase leg muscle activity during submaximal recumbent stepping in neurologically intact individuals

2013 ◽  
Vol 115 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Digna de Kam ◽  
Hennie Rijken ◽  
Toos Manintveld ◽  
Bart Nienhuis ◽  
Volker Dietz ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Vastus Lateralis ◽  
Weight Bearing ◽  
Arm Movements ◽  
Biceps Femoris ◽  
Medial Gastrocnemius ◽  
Vastus Lateralis Muscle ◽  
Rehabilitation Programs ◽  
Cord Injury ◽  
Leg Muscle

Facilitation of leg muscle activity by active arm movements during locomotor tasks could be beneficial during gait rehabilitation after spinal cord injury. The present study explored the effects of arm movements on leg muscle activity during submaximal recumbent stepping. Healthy subjects exercised on a recumbent stepping machine both with and without arm movements. Activity of five leg muscles was recorded and compared for stepping with and without arm movements. To determine which arm movements are optimal for leg muscle facilitation, subjects were instructed to step with 1) mechanically coupled vs. decoupled arm and leg movements, 2) synchronous vs. asynchronous arm movements, and 3) at 50 vs. 70 RPM. Leg muscle activity was increased by active arm movements in all muscles, except the vastus lateralis muscle. Activity of other extensors (soleus, medial gastrocnemius, and biceps femoris) was primarily increased during the extension phase, whereas activity of flexors (tibialis anterior) was also increased during the flexion phase. Facilitation was more or less consistent for both frequencies and for synchronous and asynchronous movements. For coupled arm movements, facilitation tended to be diminished or absent. The observed facilitation in the present study is probably of neuromuscular rather than biomechanical origin, since the arms are probably hardly involved in postural control or weight-bearing during recumbent stepping. Further studies in patients should explore the possibility to integrate neuromuscular facilitation in rehabilitation programs.

In vitro human masseter muscle hypersensitivity: a possible explanation for increase in masseter tone

1996 ◽  
Vol 80 (5) ◽  
pp. 1547-1553 ◽  
Author(s):  
P. J. Adnet ◽  
H. Reyford ◽  
B. M. Tavernier ◽  
T. Etchrivi ◽  
I. Krivosic ◽  
...  
Keyword(s):  
Masseter Muscle ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Threshold Concentration ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Cross Sectional ◽  
Significant Difference ◽  
Maximal Tension

To determine whether a difference in fiber-type caffeine and Ca2+ sensitivities exists between human masseter and vastus lateralis skeletal muscle, we compared the fiber-type caffeine sensitivities in chemically skinned muscle fibers from 13 masseter and 18 vastus lateralis muscles. Caffeine sensitivity was defined as the threshold concentration inducing > 10% of the maximal tension obtained after the fiber was loaded with a 1.6 x 10(-2) mM Ca2+ solution for 30 s. Significant difference in the mean caffeine sensitivity was found between type I masseter fibers [2.57 +/- 1.32 (SD) mM] vs. type I (6.02 +/- 1.74 mM) and type II vastus lateralis fibers (11.25 +/- 3.13 mM). Maximal Ca(2+)-activated force per cross-sectional area was significantly different between masseter and vastus lateralis fibers. However, the Ca2+ concentration corresponding to half-maximal tension (pCa50) was not significantly different between type I masseter (pCa50 5.9 +/- 0.02) and type I vastus lateralis muscle (pCa50 6.01 +/- 0.08). These results suggest that the increase in caffeine sensitivity of masseter muscle reflects the presence of a low reactivity threshold of the sarcoplasmic reticulum.

scholarly journals Effects of different vibration frequencies, amplitudes and contraction levels on lower limb muscles during graded isometric contractions superimposed on whole body vibration stimulation

2019 ◽  
Vol 6 ◽  
pp. 205566831982746 ◽  
Author(s):  
Amit N Pujari ◽  
Richard D Neilson ◽  
Marco Cardinale
Keyword(s):  
Isometric Contraction ◽  
Vastus Lateralis ◽  
Whole Body Vibration ◽  
Biceps Femoris ◽  
Whole Body ◽  
Isometric Contractions ◽  
Electromyographic Activity ◽  
Mean Square ◽  
Body Vibration ◽  
Neuromuscular Activity

Background Indirect vibration stimulation, i.e., whole body vibration or upper limb vibration, has been investigated increasingly as an exercise intervention for rehabilitation applications. However, there is a lack of evidence regarding the effects of graded isometric contractions superimposed on whole body vibration stimulation. Hence, the objective of this study was to quantify and analyse the effects of variations in the vibration parameters and contraction levels on the neuromuscular responses to isometric exercise superimposed on whole body vibration stimulation. Methods In this study, we assessed the ‘neuromuscular effects’ of graded isometric contractions, of 20%, 40%, 60%, 80% and 100% of maximum voluntary contraction, superimposed on whole body vibration stimulation (V) and control (C), i.e., no-vibration in 12 healthy volunteers. Vibration stimuli tested were 30 Hz and 50 Hz frequencies and 0.5 mm and 1.5 mm amplitude. Surface electromyographic activity of the vastus lateralis, vastus medialis and biceps femoris were measured during V and C conditions with electromyographic root mean square and electromyographic mean frequency values used to quantify muscle activity and their fatigue levels, respectively. Results Both the prime mover (vastus lateralis) and the antagonist (biceps femoris) displayed significantly higher (P < 0.05) electromyographic activity with the V than the C condition with varying percentage increases in EMG root-mean-square (EMGrms) values ranging from 20% to 200%. For both the vastus lateralis and biceps femoris, the increase in mean EMGrms values depended on the frequency, amplitude and muscle contraction level with 50 Hz–0.5 mm stimulation inducing the largest neuromuscular activity. Conclusions These results show that the isometric contraction superimposed on vibration stimulation leads to higher neuromuscular activity compared to isometric contraction alone in the lower limbs. The combination of the vibration frequency with the amplitude and the muscle tension together grades the final neuromuscular output.

scholarly journals Effect of hormonal growth promotants on palatability and carcass traits of various muscles from steer and heifer carcasses from a Bos indicus - Bos taurus composite cross

2008 ◽  
Vol 48 (11) ◽  
pp. 1415 ◽  
Author(s):  
R. Watson ◽  
R. Polkinghorne ◽  
A. Gee ◽  
M. Porter ◽  
J. M. Thompson ◽  
...  
Keyword(s):  
Bos Taurus ◽  
Vastus Lateralis ◽  
Carcass Traits ◽  
Bos Indicus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Cooking Methods ◽  
Triceps Brachii ◽  
The Mean ◽  
Psoas Major

The effect of several different hormonal growth promotant (HGP) implant strategies on the palatability and carcass traits of different muscles in beef carcasses was investigated using samples from heifer and steer carcasses from a Bos indicus composite breed. In experiment 1, there were seven different implant strategies evaluated in heifers that were given different combinations of up to three implants (implanted at weaning, during backgrounding and at feedlot entry). A total of 112 heifers were slaughtered and 11 muscles or portions were collected from both sides [Mm. adductor femoris, gracilus, semimembranosus, longissimus dorsi lumborum, triceps brachii caput longum, semispinalis capitis, serratus ventralis cervicis, spinalis dorsi, biceps femoris (syn. gluteobiceps), tensor fasciae latae, gluteus medius (both the ‘D’ and the ‘eye’ portions) rectus femoris, vastus intermedius, vastus lateralis and vastus medialis]. These muscles were used to prepare a total of 1030 sensory samples which were aged for either 7 or 21 days and frozen. Thawed samples were cooked using different cooking methods (grill, roast and stir frying) before being evaluated by a consumer taste panel that scored samples for tenderness, juiciness, like flavour and overall liking. Experiment 2 used the steer portion from the same calving, which were treated to a similar array of HGP strategies, except that they were given up to four implants between weaning and slaughter at ~3 years of age. In experiment 2, there was a total of 12 different HGP implant strategies tested. At boning, three muscles (Mm. psoas major, longisimuss dorsi thoracis and lumborum portions) were collected from each of 79 carcasses with a total of 237 steak samples that consumers tested as grilled steaks. For both experiments, the mean of the HGP implant strategies resulted in increased ossification scores (P < 0.05) and decreased marbling scores (P < 0.05) compared with the controls, with the effect on ossification being much larger in the older steer groups. In both experiments, the different HGP strategies decreased (P < 0.05) all sensory scores compared with the controls, for all cooking method and muscle combinations. In experiment 1, there was no interaction between the mean HGP effect and muscle (P > 0.05), and aging rates differed among the muscles (P < 0.05). In experiment 2, there was a significant (P < 0.05) muscle × HGP treatment interaction, with a decrease in tenderness score due to HGP implant strategies in the M. longisimuss thoracis and lumborum portions, compared with no significant effect in the M. psoas major. For both experiments, there were no significant differences among the different implantation strategies on sensory scores (P > 0.05).

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